Google did not reveal a timeline for the evolution to "semantic" capabilities.

Google is perpetually tuning its search engine, and in January wove content from its social network and Picasa photo-sharing service into its search formula to serve up personalized results to online queries.

"Search, plus Your World" lets people signed into Google accounts get search results that include content approved for sharing by them or friends at Google+ or Picasa.

"Let me just say that every day, we're improving our ability to give you the best answers to your questions as quickly as possible," Singhal said.

"So stay tuned for updates on what will continue to be a long road ahead."